Concentration of minerals



Patented Sept. 14, 1954 UNITED sTATEs PATENT OFFICE 2,689,045 CONCENTRATION .oF MINERALS Arthur H. Fischer, New York, N. Y., assignor to Minerec Corporation, New York, N. Y., a corporation of New York No Drawing. Application December 2, 1950, Serial No. 198,898

14 Claims. (01. 209-166) improved process for concentrating minerals by froth flotation. A specific object of the invention is to provide an improved process for concentrating sulphide minerals by froth flotation. Further specific objects of the invention are to provide improved processes for concentrating copper sulphide minerals, zinc sulphide minerals and lead sulphide minerals by froth flotation. Another object of the invention is to provide novel and effective flotation reagents. A further object of the invention is to provide new products, particularly, improved flotation reagents.

The invention is based on my discovery that a flotation froth containing a mineral collecting agent, produced in an operation employing normal frothing and conditioning agents as well as the mineral collecting agent, responds to the incorporation of a plasticizer therein in many respects as organic plastic mtaerials respond to the incorporation of the same plasticizers therein, being modified by the actions or functions of the plasticizers to form resilient, flexible and workable froths when employed even in rather minute. quantities in operations that would result in the production of brittle and unstable froths under otherwise identical conditions, even though the plasticizers themselves have no flotative capacities or properties or have only relatively insignificant fiotative capacities or properties.

The plasticizers appear to possess the ability to create or have the property of creatinga new flotative environment in which the flotation reagents employed become endowed with increased flotative powers or capacities or properties either because of improvements in one or more of the other reagents resulting from the presence of the plasticizer or because, in the flotative environment, the plasticizer itself is so influenced by the other reagents as to acquire substantial flotative qualities of an additive character.

The plasticizer accelerates distribution in flotation pulps of water-insoluble mineral collecting agents with the result that the production on the mineral particles to be recovered of films comprising the mineral collecting agent is accelerated.

The results of my researches and investigations indicate that the acceleration of distribution of the water-insoluble mineral collecting agent results from plasticization of the mineral collecting agent and that the improvements in the flotative properties of mineral collecting agents,

both water-insoluble and water-soluble, results from incorporation therein of the plasticizers with resulting plasticization.

The plasticizers and the mineral collecting agents may be mixed together prior to their introduction into the flotation pulps, or the plasticizers and the mineral collecting agents may be introduced into the flotation pulps separately. Water-insoluble mineral collecting agents and plasticizers may be mixed together prior to their introduction into the flotation pulps or they may be introduced into the flotation pulps separately with about equal advantage. Water-soluble mineral collecting agents and plasticizers preferably are introduced into the flotation pulps without preliminary mixing. Mixing of the plasticizers and the Water-insoluble mineral collecting agents may be carried out under any suitable temperature and pressure conditions. Normally, mixing of the plasticizers and the mineral collecting agents may be carried out at ordinary room temperatures and pressures prevailing in the plants in which mixing is carried out.

Incorporation of a plasticizer and a mineral collecting agent in a flotation pulp, whether mixed beforehand 0r added to the flotation pulp separately, results in the formation on particles of mineral to be recovered of films of plasticized mineral collecting agent comprising both the mineral collecting agent and the plasticizer.

When mixing of the plasticizer and the waterinsoluble mineral collecting agent is carried out prior to introduction into the flotation pulp, a plasticized mineral collecting agent is produced, and the plasticized mineral collecting agent is introduced into the flotation pulp.

When a plasticizer and a mineral collecting agent are introduced into the pulp separately,

agent is dispersed in the liquid portion of the pulp, or largely after the mineral collecting agent has formed films on the mineral particles.

When a water-insoluble mineral collecting agent is employed, the time or place of plasticization depends upon the time or order of incorporation in the pulp of the mineral collecting agent and the plasticizer. lecting agent and the plasticizer are incorporated in the pulp separately, but substantially simultaneously, plasticization of the mineral collecting agent may be eiiected largely or substantially entirely in the liquid portion of the pulp. When the plasticizer is incorporated in the pulp before or after incorporation of the water-insoluble mineral collecting agent, the degree or amount of plasticization eifected in the liquid portion of If the water-insoluble mineral col- 3 the pulp may be greater or less than the degree or amount of plasticization eiiected when they are incorporated separately but substantially simultaneously. When a water-soluble mineral collecting agent. isi'employed in" conjunction with a plasticizer,"plasticization maytake-plac'e large- Y ly or substantially entirely after the mineral collecting agent has formed films on the surface'sof the mineral particles regardless ofethew-time-or order of incorporation in the flotation pulps.

Plasticization of the mineral' collecting agent takes lace substantiallyimmediately, with substantially immediate improvement in the flotative properties of the mineral collectingagents and, in the case of Water-insoluble mineral 7collecting agents, with substantially immediate improvement in the rates and degrees of distribution of the mineral collecting agents. A particu- -lar advantage f the invention-resides inthe -f'acttha't the'iuse of a plasticizeryresults in distribution of the mineral collecting agent throughnoutthe 'fiotationpulp in a relatively short period 0f time;--as;: forexample,lin less than a half wminute When'the pulp with ia'ddedmineral col- -lecting agent and plasticizer is properly agijwit'ated'. "?he 4 plasticizer improves the capacity of the mineral collecting agent to coat the mineral particIe -Jandrapid distribution of the plastiuscized 'mineralfcollecting agent throughout the Jpulpprovides for multiplication of" the opportuni- :ties .iori the mineral collecting agent to contact andfform filmson'the mineral part'icles with a :::.consequent reduction in. the time required for 1 conditioning thepulp prior to initiation of froth- .ing operation :proper.

"in aifroth flotation operation, a conditioning 1 agent such .as'analkalinesubstance or 'an acid :substa'nce, a mineral collecting agent and 'a frothwing agent *usu'allyiare incorporatedin an aqueous :;pulp ofrtheforet 'and the pulp subsequently is subjected to aeration andagitation to produce arfrothccontaining 'th'e valuablamineral of the orey fUsually at least a brief'd p'eriod of time '.n1ay:ibe required .to condition the pulp, as by 3;. agitation ,fafter: incorporation of the conditioning awagent 'andlithe mineral collecting agent to effect l .tlioroi'igh' distribution: of .the conditioning agent and themineral-:colle'cting agent throughout the .--'.pulp* prior to. the incorporation of the frothing vagent win. the pump. IWhen a' water insoluble :mineralrcoliecting agent is. employed, in the-abfist-311061012 a plasticizer, a relativelyslong condition- .ing period; for-example, a half hour to'an hour or longer, mayrbe' required: to f eifect .distribution of: the mineral collecting agent to the extent that a'csubstantial recoverytoi valuableiminerals may -be effected.

When a' Water-insoluble mineral collecting agent is employed in: accordance with: heretofore customary'practices, the amount or per- 1 centage of valuable mineral: recovered in-the flotation-operation is afunction of. the time of conditioning to effect distribution of the mineral collecting. agentand filming of thermineral particlesw If preliminary conditioning prior' to "flotation is not provided for, or, if a relatively short period of conditioning is rovided for, recovery of valuableminerals may be so low as tomake the operation unprofitable"or'uncommercial. Inuflotation. operations conducted-heretofore, the amount of recovery, or the percentage recovery,. of-valuable. mineral is a'function ofthe amount of mineraLcollecting agent-thatforms films on the mineral-:-partic1es,- and,'tosomeextent,- the amount-of mineral collectingagent particles is employed. Consequently, the amount i {of mineral collecting agent that can be employed effectively -isrestrictecl and recoveries are rela- ""tivelypoor. -Also, the use of excess water-in- .:=.so1ub1e mineral collecting agent, that is, mineral -E'01160ti11g agent that does not form films on the mineral particles, results in the production of a "poorfr'oth in thesubsequent frothing operation which further limits the recovery of valuable min- "eral.

.'Thepresentinventionpermits the incorpora- :;.tioni'in'-.the"pulp andsthe 'eifective'use of an .r

r. :tamountt of mineral collecting agent 'suificient to form proper -films .:0n"a11i minera1 particles.

,5 A further-important advantage of the-invention': results from the fact that rapid distribution *of a water-iin'soluble mineral collecting agent is effected vvith :consequent shortening or eliminaa-"tion oiiithercond-itioning perioolx For example; in

- ar mineral" recovery or concentration plant in 30. :Which acconditioning'period of a half hour.v or

.1 an hour is required to produce asuitable recovery rand in which the time offiow of the pulp through v:nthefrothingroperation is" about fifteen minutes,

conditioning facilities must be provided for hanszdlingtwo or four times the: amount of pulp actually subj ected F130? the. frothing operation 'or 'min- ":eral 'rec'ovcry"operation proper, with attendant 1 increasedi costs of installation, maintenance: and

operationw When; inaccordance' with the present 40 invention, the time required for conditioning is -=reduced*to a. halfrminute'or "less, conditioning wequipmentcan' bevsub'stantially completely 'dis- 4 pensed withy and the conditioning and mineral collecting agentscanbe'added to the pulp in a 4,5 "smallicompartment immediately ahead of the wii'rst: frothing compartment. This advantageous ..'result of theinventionpermits the immediateruse 11in lants=not ,=equipped with conditioning equipmerit of "highly efficacious -:vvater-insoluble mineral collecting. agents: that otherwise cannot be em- :-ployed-:effectively.

.-- It. istube-understood that the: scope. of the invention is not to bewlimited-bytheoretical discussions contained herein. Whatever-.thesexplana- =tion =maybe, it is a'zdemonstrable fact'that the incorporation. in: a-zfiotation" pulp to which is addecl a; mineral:collectingagentandithe normal frothingl andxconditicning agents: of a plasticizer- -normally. effective for plasticizing organic plas- .-tics n wamounts' even as small as five one- .thousandths- (0.0051 of a pound per ton of ore treated. :may-result. in the production of profound improvements inthe flotation operation and in the metallurgybf themineral or metal recovery ,,operationcof which the flotation operation is a part. -Theaddition of theplasticizer (1)- 'Pro'duces a resilient, flexible and workable froth in a flotation operation that would pro- 1 duce a 'brittle and unstable froth under'other- 79 :Wise- -identica'l condition,

l- (2)"Permits the application of more mineral colrlecting .:agentL forincreased collecting power 'swithoutid'etriment to the froth,

-*('3) Reducesrthetttime necessary for conditioning :.:Lthewpulptwitlrthtgmineral collecting agent,

(4) Increases the speed of the flotation operation and (5) Yields generally improved metallurgical results. i

The intimate relationship of dispersed and dispersing phases involved in the plasticizer effect is felt not onl in the conditioning process but, also, in the process of froth formation and results in an over-all improvement in the mechanics of the operation.

The plasticizer preferably is employed in amounts in the range 0.01 to 0.005 pound per ton of ore treated, but it may be employed in greater or lesser amounts when conditions warrant such modification.

Among th commonly known plasticizers that I have found to be highly efiective in flotation operations are included esters of phthalic acid, sebacic acid, citric acid, tartaric acid, phosphoric acid, succinic acid and hydroxybenzoic acid such as salicylic acid, such, for example, as

Diethyl phthalate Dibutyl phthalate Dihexyl phthalate Dibutyl sebacate Dihexyl sebacate Tributyl citrate Triamyl citrate Dibutyl tartrate Diamyl tartrate Tricresyl phosphate Diamyl succinate Amyl salicylate Diethyl adipate Dibutyl adipate Dihexyl adipate While the plasticizers may be employed with advantage in conjunction with all mineral collecting agents, including both water-soluble and water-insoluble mineral collecting agents, employed in flotation practice with the normal frothing and conditioning agents, my researchers and investigations indicate that plasticizers are most effective. and better results are obtained when they are employed in conjunction with the water-insoluble alkyl xanthogen formates, both symmetrical and unsymmetrical. Other specific mineral collecting agents with which plasticizers may be employed advantageously include, for example, alkali metal Xanthates and dialkyl dithiophosphates. Representative xanthogen formate compounds suitable for use as mineral collecting agents include Ethyl xanthogen ethyl formate Butyl xanthogen ethyl formate Amyl xanthogen ethyl formate Hexyl Xanthogen ethyl formate The claims of this application are directed to methods or processes employing esters of polybasic acids and esters of dibasic acids of the types of tartaric acid, sebacic acid, succinic acid and adipic acid. Methods or processes employing plasticizers in the forms of esters of others of the acids referred to herein are covered by my copending applications Serial No. 198,896, filed December 2, 1950, Serial No. 198,897, filed December 2, 1950, and Serial No. 198,899, filed December 2, 1950.

The plasticizer and the mineral collecting agent employed in an flotation operation in accordance with the invention may be added to the flotation pulp separately or in the form of any suitable mixture or solution.

In practicing a method or process of the invention, a neutral, acid or alkaline circuit may be employed.

The following examples illustrate the advantages of the reagents and processes of the invention over reagents and processes employed heretofore.

In carrying out the processes of the examples, sulphide ores of the compositions indicated with respect to copper and zinc were ground in water to form aqueous pulps which were subjected to froth flotation operations in the presence of the reagents indicated, but, otherwise, under substantially identical conditions, withthe production of concentrates and tailing products of the analyses indicated:

Example I Test No 1 2 Heads, team On 3. 31s Concentrates, percent Cu 18.19 Tails, percent Cu Reagents:

Lime .pounds per ton. 11.0 11. 0 Pine oil d0 .12 .12 Hexyl xanthogen ethyl formatedo. 05 05 Dibutyl sebacate do. 01

Example II Test N0 1 2 Heads, percent Cu 4.114 4.106 Concentrates, percent Cu. 25.17 22.12 Tails, percent u .222 .184

eagents:

Lime pounds per tom. 10. 0 10. 0 Pine oil do 09 .09 Amyl Xanthogen ethyl formats.-. -do .04 04 Dibutyl tartrate .do .01

Example III Test N0... Q. 1 2

Heads, percent Cu 4. 422 Concentrates, percent Cu 24.56 Tails, percent Cu .203 Reagents:

Lime pounds per ton 10.0 10. 0 Pine oil dol .12 .12 Hexyl xanthogen ethyl formate- -.do 04 04 Dibutyl tartrate do .01

Example IV Test No.1 1 2 3 Heads, percent Cu 4.104 3. 945 4.104 Concentrates, percent Cu... 24.46 23. 04 23. 24 Tails, percent Cu .222 .190 .196 Reagents:

Lin1e pounds per min. 10.0 10. 0 10. 0 Pine oil .1 0..-. .12 .12 .12 Any] xanthogen ethyl formate d 04 .04 .04 Dibutyl tartrate .do 01 Diamyl tartrate do .01

Example V Test No 1 2 3 4 Heads, percent Cu 4.104 4.104 3.945 4.109 Concentrates, percent Cu 24. 46 23. 24 23.04 22. 43 Tails, percent Cu .222 .196 .19 .209 Reagents:

Lime pounds per ton 10.0 10.0 10. 0 10. 0 Pine oil o .12 .12 .12 .12 Amy] xanthogen ethyl formate pounds per ton" 04 04 .04 04- Diamyl tartrate .do Dibutyl tartrate .do Dibutyl succinate. .do.

aepsepas 7 in Example -'VI Test No 1 1 2 -Heads,'percent Cu .494 4. 482 Concentrates,-percent Cu. .n 21. 27 21. 37 Tails, percent Cu 216 .19 Reagents:

Lime -.pounds per ton 10.0 10.0 P'me oil do .12

Hexyl xanthogen ethyl fol-mate- "do" .04 04 -Diamyl tartrate do .005

Example VII ""--'Te st'No l 2 Heads, percent Cu 2. 045 2.070 Concentrates, percent Cu" 14.61 14. 40

Tails, percent Cu .300 242 Reagents:

Sulphuric} acid pounds per ton 10. 10. 0 Gresylic acid H, do .44

'flest No l 2 3 4 Heads, percent.Ou 2.063 2.036 2. 073 2. 03a

. Concentrates, percent Cu 14. 71 15.84 12.87

Tails, percent 011 "30 .262 280 .242 Reagents: v

Sulphuric acid pounds per mm. 100 1 0.0 10.0 .--10.0 Cresylic acid .do. 44 .44 44 44 Ethyl xanthogen ethyl formatel pounds per ton. 20 .20 20 Diaxnyl tartratel Dibutyl tartrate Dibutyl sebacate .do. 02

Example IX Test No 1 2 Heads, percent Cu 4-. 393 Concentrates, percent Cu 18.09

; Tails,- percent Cu .l .197

- Reagents:

, Sodium ethyl xanthates pounds per ton 06 .06 Potassium amyl xanthate d l... 01 .01 Dibutyl sebacate .do 01 Example X Test N o l 2 Heads, percent Cu l 800 .800 Concentrates, percent Cu. 9. 63 9. 83

Tails, percent Cu. l 091 .078

Reagents:

, Lime ....pounds perton 4. 0 4. 0

Pine oil o .11 .11 '.02 .02 Dihexyl sebacate do. .005

In the tests carried out to obtain the data set forth in the above examples, the froth produced in eachof the tests in which aplasticizer was employed was resilient, flexible and workable,

, whereas in each of the tests carried out without the use of a plasticizer, amore brittle and less I stablefroth was produced.

I claim: j 1. The method of concentrating a 'sulphide mineral Which comprises subjecting the sulphide t minerahhearingmaterial in the form of a pulp consisting of alkyl Xanthogen formatesfalkali 'to a froth flotation operation in the presence of a mineral collecting agent selected from theclass .ing'of diamyl succinate'; dibutyl anddiamyl tartrates, dibutyl and dihexyl sebacates, diethyl adipate, dibutyl adipate and dihexyl adipate.

1:; 2: Theismethod of concentrating; a-: "si"1lphide mineral which comp-rises subjecting the sulphide -s.-mineral-bearing material in the form" of a pulp to a froth flotation operation in the presence of van alkyl xanthogen mineral collectingv agent and v jd'ibutyl tartrate.

f 3.".The 'method of concentrating a sulphide lmineraliwhich comprises subjecting the. sulphide 'mi'rieral bearing.material"inthe form-'of a pulp to a froth flotation operation in the-presenceof amyLxanthogen ethylformate and dibutyl tar- "itrate. 4.1The. method "of. concentrating a" sulphide I mineraliwhichlcomprises subjecting the sulphide mineral-bearing m'aterialin the formfof a pulp .to a froth flotation operation in the presence of an alkyl. .xanthogen formate mineral collecting ag'entand diamyl tartrate.

5. The methodfof concentrating a .sulphide 0,-, mineral? which comprises subjecting 3 sulphide mineral-bearing materialin the form-of a pulp to a frothflotation operation in the presence of ethyl Xanthogen'ethylformateand diamyl tartrate. I

6. The methodof' 'conoentrating a sulphide mineral which comprises subjecting the sulphide mineral-bearing' material in the form of a pulp'to a frothilotationoperation in the presence of an alkyl Xanthogenformate mineral collecting agent andwdibutyl-sebacate.

7. The method of concentrating a sulphide mineral which comprises subjecting the sulphide mineral-bearing material in the form of a pulp to a froth flotationo'peration'in the presence of hexyl xanthogen'i'et-hyl .lf'ormate and dibutyl sebacate. V

8. The method of concentrating a sulphide 1:. Jmineral which comprises subj ectin'g the sulphide "imineralbearinga'rnaterial"inl-the form' of a pulp to afrOthflOtation operation in the presence of ethyllxanthogen ethyl formate and dibutyl sebwacate.

method-"of concentrating a sulphide mineral which comprises subjecting the sulphide v-mineral-loearing. material inthe form of a pulp to a'frothflotation-operation in the' presence of Y (an alkali metal alkyl xan'thatei mineral collectingiagent and dibutyl sebacate.

510'. The'irnethod of con'centrating asulphide minerar which. comprises subj ecting'. the sulphide mineral-hearing material in theform'of a pulp to afroth notation operation in the presence I of odium and potassium amyl xanthates and dibutyl sebacate.

11. Arflotation agent forusein a sulphide mineral concentrating process" in which sulphide minerahbearingmaterialilinthe form of a pulp is subjectedto afrothflotation in the presence of frothing and mineral collecting agents, said flotation agentabeingan intimate mixture comprising (1). a water-insoluble mineralcollecting aegentlselected from the group consisting of alkyl x anthogen formates and-(29 a plasticizer selected from the group consisting of 'dialkyl-succinates,

- tartrates,- 'seb'acates and-adi'pates.

l2-'.'-A--flotation agent--for use in a--sulphide mineral concentrating process inwhich sulphide mineral-bearing rnaterialg-in'the form, of a pulp "is subjected to a froth-flotation-in the presence of frothing' and mineralcollecting agents, said flotation agent loeing an intimatemixture comprising 7 1(1) a rwatereinsoluble' 'minerall'collecting agent "selected'frorn' the group-consistingofethyl, butyl, 'ainyl and h'e'xyl 'Xarith'ogeri Iethyl;formates-, and 5 (2) a plasticizer selctedfr'omthe group consisting of dialkyl succinates, tartrates, sebacates and adipates.

13. A flotation agent for use in a sulphide mineral concentrating process in which sulphide mineral-bearing material in the form of a pulp is subjected to a froth flotation in the presence of frothing and mineral collecting agents, said flotation agent being an intimate mixture comprising (1) a water-insoluble mineral collecting agent selected from the group consisting of alkyl xanthogen formates and (2) a plasticizer selected from the group consisting of diamyl succinate, dibutyl and diamyl tartrates, dibutyl and dihexyl sebacates, and diethyl, dibutyl and dihexyl adipates.

14. A flotation agent for use in a sulphide mineral concentrating process in which sulphide mineral-bearing material in the form of a pulp is subjected to a froth flotation in the presence of frothing and mineral collecting agents, said flotation agent being an intimate mixture comprising (1) a water-insoluble mineral collecting agent selected from the group consisting of ethyl, .butyl, amyl and hexyl xanthogen ethyl formates and (2) a plasticizer selected from the group consisting of diamyl succinate, dibutyl and diamyl tartrates, dibutyl and dihexyl sebacates, and diethyl, dibutyl and dihexyl adipates.

10 References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 962,678 Sulman et al June 28, 1910 1,652,099 Douglass Dec. 6, 1927 2,065,053 Christmann et a1. Dec. 22, 1936 2,099,120 Kirby et a1 Nov. '16, 1937 2,251,217 Woodhouse July 29, 1941 2,349,094 Heilmann May 16, 1944 2,373,688 Keck Apr. 17, 1945 2,410,376 Booth et a1 Oct. 29, 1946 FOREIGN PATENTS Number Country Date 19,644 Australia Oct. 10, 1934 OTHER REFERENCES Plasticizers for Adhesives etc., 1944 by Carbide and Carbon Chemicals Corporation, pages 2-5. (Copy in Scientific Library.)

Taggart, Handbook of Mineral Dressing, 1945, section 12, page 42. (Copy in Division 25.)

Hackhs Chemical Dictionary, Third Edition, printed in 1946, page 664. (Copy in Division 25.) 

1. THE METHOD OF CONCENTRATING A SULPHIDE MINERAL WHICH COMPRISES SUBJECTING THE SULPHIDE MINERAL-BEARING MATERIAL IN THE FORM OF A PULP TO A FROTH FLOTATION OPERATION IN THE PRESENCE OF A MINERAL COLLECTING AGENT SELECTED FROM THE CLASS CONSISTING OF ALKYL XANTHOGEN FORMATES, ALKALI METAL XANTHATES, AND DIALKYL DITHIOPHOSPHATES AND A PLASTICIZER SELECTED FROM THE GROUP CONSISTING OF DIAMYL SUCCINATE, DIBUTYL AND DIAMYL TARTRATES, DIBUTYL AND DIHEXYL SEBACATES, DIETHYL ADIPATE, DIBUTYL ADIPATE AND DIHEXYL ADIPATE. 